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81.
ABSTRACTPolicy evaluation has grown significantly in the EU environmental sector since the 1990s. In identifying and exploring the putative drivers behind its rise – a desire to learn, a quest for greater accountability, and a wish to manipulate political opportunity structures – new ground is broken by examining how and why the existing literatures on these drivers have largely studied them in isolation. The complementarities and potential tensions between the three drivers are then addressed in order to advance existing research, drawing on emerging empirical examples in climate policy, a very dynamic area of evaluation activity in the EU. The conclusions suggest that future studies should explore the interactions between the three drivers to open up new and exciting research opportunities in order to comprehend contemporary environmental policy and politics in the EU. 相似文献
82.
In search of human-associated bacterial pathogens in Antarctic wildlife: report from six penguin colonies regularly visited by tourists 总被引:4,自引:0,他引:4
We investigated the potential role of Antarctic tourism in the introduction of human-associated pathogens into Antarctic wildlife. We collected and analyzed 233 fecal samples from eight bird species. The samples were collected at six localities on the Antarctic Peninsula, which often is visited by tourists. Every sample was investigated for pathogens of potential human origin: Campylobacter jejuni, Salmonella spp., and Yersina spp. None of these bacteria was found. Our data suggest that the tourism industry so far has achieved its goal of not introducing pathogens into the Antarctic region. There is, however, an urgent need to further investigate the situation in areas closer to permanent Antarctic settlements. 相似文献
83.
Dynamics of Turbulence in Low-Speed Oscillating Bottom-Boundary Layers of Stratified Basins 总被引:1,自引:0,他引:1
Lorke Andreas Umlauf Lars Jonas Tobias Wüest Alfred 《Environmental Fluid Mechanics》2002,2(4):291-313
This paper focuses on the impact of an oscillating low-speed current on the structure and dynamics of the bottom-boundary layer (BBL) in a small stratified basin. A set of high-resolution current profile measurements in combination with temperature-microstructure measurements were collected during a complete cycle of the internal oscillation (`seiching') in the BBL of Lake Alpnach, Switzerland. It was found that even a relatively long seiching period of 24 hours significantly changed the form of the near-bottom current profiles as well as the dynamics of the turbulent dissipation rate compared to the steady-state law-of-the-wall. A logarithmic fit to the measured current profiles starting at a distance of 0.5 m above the sediment led to inconsistent estimates of both friction velocity and roughness length. Moreover, a phase lag between the current and the turbulent dissipation of 1.5 hours and a persistent maximum in the current profile at a height of 2.5 to 3 m above the sediment were observed. The experimental findings were compared to the results of a k- turbulence model and showed good agreement in general. Specifically, the inconsistent logarithmic fitting results and the observed phase lag were reproduced well by the model. 相似文献
84.
Matthias Schmid Torsten Hothorn Kelly O. Maloney Donald E. Weller Sergej Potapov 《Environmental and Ecological Statistics》2011,18(4):709-733
Indices of biotic integrity have become an established tool to quantify the condition of small non-tidal streams and their watersheds. To investigate the effects of watershed characteristics on stream biological condition, we present a new technique for regressing IBIs on watershed-specific explanatory variables. Since IBIs are typically evaluated on an ordinal scale, our method is based on the proportional odds model for ordinal outcomes. To avoid overfitting, we do not use classical maximum likelihood estimation but a component-wise functional gradient boosting approach. Because component-wise gradient boosting has an intrinsic mechanism for variable selection and model choice, determinants of biotic integrity can be identified. In addition, the method offers a relatively simple way to account for spatial correlation in ecological data. An analysis of the Maryland Biological Streams Survey shows that nonlinear effects of predictor variables on stream condition can be quantified while, in addition, accurate predictions of biological condition at unsurveyed locations are obtained. 相似文献
85.
86.
The complex songs of songbirds are thought to have evolved through sexual selection. Sexually selected signals must be associated
with costs in order to ensure their honesty as indicator of male quality. Costs may relate to the development of the neural
substrate underlying song learning, which develops already very early in life. Song may, therefore, serve as an indicator
of the early developmental history. This nutritional stress hypothesis has initially been confirmed for a variety of species,
but recent studies using zebra finches as a model species reported somewhat inconsistent effects, and the functional consequences
of changes in adult song phenotype remain unclear. We tested the nutritional stress hypothesis in canaries by manipulating
either the brood size or the food quality postfledging. The brood size manipulation had a significant effect on early development,
and low food quality postfledging led to a transient reduction in body mass. However, we did not find evidence that any of
the song traits measured reflected the early developmental conditions, which is in conflict with the nutritional stress hypothesis.
Canaries may be less vulnerable to nutritional stress or are able to compensate stressful conditions during early development.
However, if males compensated, this compensation may have come at a survival cost. Female mate choice decisions were independent
of the developmental history of a male. Instead, females preferred males singing longer song bouts, a trait that may contain
a heritable component. 相似文献
87.
Sarah E. Crawford Catrina Brüll nee Cofalla Benedikt Aumeier Markus Brinkmann Elisa Classen Verena Esser Caroline Ganal Elena Kaip Roger Häussling Frank Lehmkuhl Peter Letmathe Anne-Katrin Müller Ilja Rabinovitch Klaus Reicherter Jan Schwarzbauer Marco Schmitt Georg Stauch Matthias Wessling Süleyman Yüce Markus Hecker Karen A. Kidd Rolf Altenburger Werner Brack Holger Schüttrumpf Henner Hollert 《Environmental Sciences Europe》2017,29(1):23
Protecting our water resources in terms of quality and quantity is considered one of the big challenges of the twenty-first century, which requires global and multidisciplinary solutions. A specific threat to water resources, in particular, is the increased occurrence and frequency of flood events due to climate change which has significant environmental and socioeconomic impacts. In addition to climate change, flooding (or subsequent erosion and run-off) may be exacerbated by, or result from, land use activities, obstruction of waterways, or urbanization of floodplains, as well as mining and other anthropogenic activities that alter natural flow regimes. Climate change and other anthropogenic induced flood events threaten the quantity of water as well as the quality of ecosystems and associated aquatic life. The quality of water can be significantly reduced through the unintentional distribution of pollutants, damage of infrastructure, and distribution of sediments and suspended materials during flood events. To understand and predict how flood events and associated distribution of pollutants may impact ecosystem and human health, as well as infrastructure, large-scale interdisciplinary collaborative efforts are required, which involve ecotoxicologists, hydrologists, chemists, geoscientists, water engineers, and socioeconomists. The research network “project house water” consists of a number of experts from a wide range of disciplines and was established to improve our current understanding of flood events and associated societal and environmental impacts. The concept of project house and similar seed fund and boost fund projects was established by the RWTH Aachen University within the framework of the German excellence initiative with support of the German research foundation (DFG) to promote and fund interdisciplinary research projects and provide a platform for scientists to collaborate on innovative, challenging research. Project house water consists of six proof-of-concept studies in very diverse and interdisciplinary areas of research (ecotoxicology, water, and chemical process engineering, geography, sociology, economy). The goal is to promote and foster high-quality research in the areas of water research and flood-risk assessments that combine and build off-laboratory experiments with modeling, monitoring, and surveys, as well as the use of applied methods and techniques across a variety of disciplines. 相似文献
88.
Anwar Zahid M. Q. Hassan G. N. Breit K.-D. Balke Matthias Flegr 《Environmental geochemistry and health》2009,31(Z1):69-84
Accumulations of iron, manganese, and arsenic occur in the Chandina alluvium of southeastern Bangladesh within 2.5 m of the
ground surface. These distinctive orange-brown horizons are subhorizontal and consistently occur within 1 m of the contact
of the aerated (yellow-brown) and water-saturated (gray) sediment. Ferric oxyhydroxide precipitates that define the horizons
form by oxidation of reduced iron in pore waters near the top of the saturated zone when exposed to air in the unsaturated
sediment. Hydrous Fe-oxide has a high specific surface area and thus a high adsorption capacity that absorbs the bulk of arsenic
also present in the reduced pore water, resulting in accumulations containing as much as 280 ppm arsenic. The steep redox
gradient that characterizes the transition of saturated and unsaturated sediment also favors accumulation of manganese oxides
in the oxidized sediment. Anomalous concentrations of phosphate and molybdenum also detected in the ferric oxyhydroxide-enriched
sediment are attributed to sorption processes. 相似文献
89.
Matthias Demuzere Nicole P.M. van Lipzig 《Atmospheric environment (Oxford, England : 1994)》2010,44(10):1341-1355
In order to make projections for future air-quality levels, a robust methodology is needed that succeeds in reconstructing present-day air-quality levels. At present, climate projections for meteorological variables are available from Atmospheric-Ocean Coupled Global Climate Models (AOGCMs) but the temporal and spatial resolution is insufficient for air-quality assessment. Therefore, a variety of methods are tested in this paper in their ability to hindcast maximum 8 hourly levels of O3 and daily mean PM10 from observed meteorological data. The methods are based on a multiple linear regression technique combined with the automated Lamb weather classification. Moreover, we studied whether the above-mentioned multiple regression analysis still holds when driven by operational ECMWF (European Center for Medium-Range Weather Forecast) meteorological data. The main results show that a weather type classification prior to the regression analysis is superior to a simple linear regression approach. In contrast to PM10 downscaling, seasonal characteristics should be taken into account during the downscaling of O3 time series. Apart from a lower explained variance due to intrinsic limitations of the regression approach itself, a lower variability of the meteorological predictors (resolution effect) and model deficiencies, this synoptic-regression-based tool is generally able to reproduce the relevant statistical properties of the observed O3 distributions important in terms of European air quality Directives and air quality mitigation strategies. For PM10, the situation is different as the approach using only meteorology data was found to be insufficient to explain the observed PM10 variability using the meteorological variables considered in this study. 相似文献
90.
Marine Elbakidze Kjell Andersson Per Angelstam Glen W. Armstrong Robert Axelsson Frederik Doyon Martin Hermansson Jonas Jacobsson Yurij Pautov 《Ambio》2013,42(2):160-173
This paper analyzes how sustained yield (SY) forestry is defined and implemented in Sweden and Russia, two countries with different forest-industrial regimes. We first compare definitions of SY forestry in national legislation and policies. Then we study forest management planning in two large forest management units with respect to: delivered forest products and values, how the harvest level of timber is defined, where the harvest takes place, and what treatments are used to sustain desired forest products and values. In Sweden SY forestry is maximum yield based on high-input forest management, and in Russia it is forestry based on natural regeneration with minimum investments in silviculture. We conclude that how SY forestry contributes to SFM depends on the context. Finally, we discuss the consequences of SY forestry as performed in Sweden and Russia related to its ability to support diverse forest functions, as envisioned in sustainable forest management policy. 相似文献